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Code: Select all

[GLOBAL print_one]
[GLOBAL printk]

screen_x	equ 0
screen_y	equ 0
string		db "Hello, World!", 0

new_line:
    mov		byte [screen_x], 0
    add		byte [screen_y], 1

    ret

print_one:
; Temporarily use bx as a storage spot for the attrib/char
    mov		bh, 0x0F
    mov		bl, al

; Multiply the screen_y by 160 and put it in cx (attrib/char each column, times 80 columns per row)    
    mov		ax, [screen_y]
    mov		cx, 160
    mul		cx
    mov		cx, ax

; Multiply the screen_x by 2 and put it in dx (attrib/char each x value)
    mov		ax, [screen_x]
    mov		dx, 2
    mul		dx
    mov		dx, ax

; Put the attrib/char back into ax
    mov		ax, bx

; Put the x and y values into bx
    mov		bl, dl
    mov		bh, cl

; Put the video memory location into edi, then add on the x and y values
    mov		edi, 0xb8000
    mov		[es:edi], bx

; Put the attrib/char into video memory (At this time - AX=ATTRIB+CHAR, BX=X+Y, ES:EDI=VIDEO MEMORY+BX, DX=X, CX=Y)
    stosw

; Increment x
    add		byte [screen_x], 1

; If the x value is on the last value, goto a new line.
    cmp		byte [screen_x], 80
    je		new_line

    ret

printk:
; Put the sring in al, increment si, which contains a pointer to a string
    lodsb
    inc		si

; If al = 0x00, end of string
    cmp		al, 0
    je		   done

; Else, print the character
    call	print_one
    jmp       printk

done:
    mov	al, 'D'
    call	print_one

    call	new_line

Code: Select all

column dw 0
row dw 0
string db "Hello, World!", 0
string2 db "Next test in progress...",0
done db "All test sucessfull!",0

mov si,string 
call printk
mov si,string2
call printk
mov si,done
call printk
cli
hlt

printk:
	mov ax,0xb800
	mov es,ax
	call printchar
	ret

printchar:
	mov di,[row]
	mov al,[si]
	cmp al,0
	jz finished
	mov [es:di],al
	mov bx,[row]
	inc bx
	inc bx
	mov [row],bx
	inc si
	jmp printchar

finished:
	call nextline
	ret

nextline:
	xor ax,ax
	mov ax,[column]
	inc ax
	mov [column],ax
	mov bx,[row]
	xor bx,bx
	mov cx,160
	mul cx
	mov [row],ax
	ret